Genomicron: Phylogenetic fallacies: "early branching equals primitive".

T Ryan Gregory at Genomicron who is an evolutionary biologist specializing in genome size evolution at the University of Guelph in Canada educates us (and perhaps some ID proponents) about some of the common pitfalls in phylogeny. In this case, the posting discusses the findings in a recent paper which argues that the comb jellies and not sponges are the earliest branch.

Some have uncritically repeated the LiveScience report “Shock: First animal on Earth was surprisingly complex”

Earth’s first animal was the ocean-drifting comb jelly, not the simple sponge, according to a new find that has shocked scientists who didn’t imagine the earliest critter could be so complex.

as Ryan points out

This interpretation illustrates a common misconception about evolutionary trees, one that I addressed in a recent paper on the topic (Gregory 2008b). Specifically, it draws the false conclusion that a modern member of an early branching lineage is very similar to the distant ancestor that it shares with other lineages. In actuality, the species under consideration are all modern species whose lineages have been evolving for exactly the same amount of time since their divergence from a common ancestor. The comb jelly lineage may have branched first, but the common ancestor from which it and the other animals lineages diverged probably looked nothing like a comb jelly. It is entirely possible that comb jellies are highly derived (i.e., very different from their early ancestor), just as other animal lineages are.

It should come as no shock to most of us that the LiveScience report was uncritically quoted even though they actual paper and the LiveScience report explains the impact of the findings.

Even less of a surprise is that the authors who uncritically quoted the LiveScience report were our idnet.com.au friend at Uncommon Descent as well as Mike Gene at TelicThoughts (also here) and our friend Casey Luskin at EvolutionNews.org

What a nice display of “Stupid is as stupid does”, these ID proponents read something which appears to contradict earlier science findings, see the word ‘complex’ and immediately jump to the (wrong) conclusion. Is this the kind of ‘science’ you want to be taught in schools?

Genomicron is an excellent science website and the following papers seem quite interesting.

Gregory, T.R. 2008a. Evolution as fact, theory, and path. Evolution: Education and Outreach 1: 46-52.

Gregory, T.R. 2008b. Understanding evolutionary trees. Evolution: Education and Outreach 1: 121-137